CppunitTest_sw_htmlexport: enable on OS X

Change-Id: I2aa954b0f97de9ae7657ae3a12d1a15389c13ef2
Reviewed-on: https://gerrit.libreoffice.org/11159
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>